• Journal of the Korean Geotechnical Society
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• v.37 no.3
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• pp.31-41
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• 2021

A dozer is a construction machinery used to move soil mass along large open tracts of land. Soil thrust generated on the soil-track interface determines the performance of the dozer; to improve the tractive performance of the dozer, the outer surface of the continuous-track is designed to protrude with grousers. In this study, we calculated soil thrust of the dozer equipped with grousers with various shape ratios, and evaluated the optimal grouser shape ratio considering ground conditions. Grouser generated additional soil thrust on the side of the continuous-track (e.g., side soil thrust) and converted the shearing surface (e.g., from soil-track interface to soil-soil interface), increasing the soil thrust of dozer by about 1.3 to 1.6 times. The effect of grouser's shape ratio on the soil thrust of dozer differed with the relative density of the ground. As the shape ratios of grouser increased, soil thrust of dozer decreased at the relative density of 40% and increased at the relative density of 80%. Based on these results, it can be concluded that the shape ratio of grouser severely affects the dozer's performance; thus, careful consideration of the optimal shape ratio of grouser is of great importance in the mechanical design, evaluation, and optimization of the undercarriage of dozers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.123-130
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• 2006

The purpose of the paper is to make the three dimensional road simulation model based on the digital photogrammetry and GIS techniques in the middle of Halla mountain of Jeju island. To do this, we generate DEM (digital elevation model) and digital ortho image using GIS tools such as Arc View, Imagestation and MGE module. In GIS, the overlay map schemes combining of the hill shade, the land slope and aspect were applied. Based on the processes, we can build the best three dimensional road line along the hill side of the island. From the results, we also found that the derived DEM from digital ortho image and the GIS technique were very useful for choosing the best three dimensional road design before the real road construction works in Jeju island.

• The Journal of Fisheries Business Administration
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• v.11 no.1_2
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• pp.115-155
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• 1980

Nowadays managers of fisheries enterprises and users of accounting information have a considerable interest in the fishery right. The fishery right, which is given by administrative quarters, is referred to exclusive fishing right in a certain coastal fishing ground, and it has been one of the property rights since the turn of the century. The main purpose of this study is to provide an improved accounting method of the fishery right from the side of accounting. To achieve this purpose, legal nature of the fishery right should be understood in the first place, for the fishery right, an intangible asset, is a sort of property right guaranteed by the fisheries laws, According to the basic law in the fisheries "Fisheries Law, " the fishery right is broken down largely into three categories; culture fishing right, set fishing right and common fishing right. The legal characteristics of these fishery rights are as followings: 1. The fishery right is a private right. 2. The fishery right is a property right. 3. The fishery right is a right in rem, and legal provisions pertaining to land are applied to the fishery right with necessary modifications. In addition to the above fishery rights, the Fisheries Law provides some provisions on the so-called entrance right, and those who obtained the right are authorized to access to a certain common fishing right fishing ground where they have been traditionally fishing. In the inland fisheries, the fishery right system similar to that of the coastal fisheries discussed above is adopted in conformity with the Inland Fisheries Developing and Expediting Law. Viewing from an angle of accounting, there are two kinds of additional fishing rights which are dealt as assets. These fishery rights dealt as asset include the license of entry in the so-called permitted fishing which is also called as fishery right in plain language, and tile entrance right obtained abroad. Although these two kinds of rights are not the fishery right from a viewpoint of law, they are regarded as fishing rights in accounting which intends to provide a useful economic information.formation.

• Journal of architectural history
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• v.18 no.6
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• pp.85-101
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• 2009

The Purpose of this paper is a study on the characteristics of Campidoglio hill plan by Michelangelo. 1. The plan of the Campidoglio hill is composed of the harmonized and united space, in spite of the existing conditions of a steep flight of land, a irregular site shape, a building of each other different dimension and form. And it is newly changed by site left through the modification of existing building elevation, utilization of existing building for new planning, connection with existing building and newly planned building from plaza composition of trapezoid form. 2. The concept of planning of the Campidoglio hill is planned by compromising for requirements of Baroque after Renaissance which urban planning characteristics of Baroque is as the relation with urban street through a inclined stairs and process such as street-approach stairs-plaza-symbol of inside plaza-building. 3. The section plan of the Campidoglio hill is planned by which can be easily approached to the plaza through the inclined stairs of gentle angle from street at the center east-west direction of main axis such as main axis, utilizing the existing site shape, and it is composed of the convex shape ascending gently at the center central part of the plaza. 4. The plan of the Campidoglio hill is composed of the elation with the axis of existing Senatorio palace, building planning of perfect balance, plaza composition of reversed trapezoid form bybuilding planning, central concentrated planning of buildings surrounding plaza. 5. The three palace of the plan of the Campidoglio hill is composed of the concept as theater which the stage background forms the front elevation of Senatorio palace higher two palace and the wings of either side of stage form the front elevation of Conservatori palace and Nuovo palace, surrounding three palace elevation around plaza of trapezoid form.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.84-97
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• 1983

Under the limited arable land, the enhancement of agricultural productivity is indispensable to provide the food demand which is concomitant with the rapid increase in population. From this viewpoint, the upbringing and dissemination of high-yielding varieties has been promoted continuously and several modifications in cultural practices, including heavy fertilization, dense planting, and early transplanting, also have been gradually developed. However these changes in cultivation have led to the increased outbreak of insect pests and diseases. And this unexpected results have accelerated the number and complexity of pesticides employed as well as their consumption. Even though pesticides are essential materials contributing to the steady production of agricultural crops, large scale consumption of them has given rise to several adverse impacts, such as mammalian hazard and/or environmental contamination. In this respect, recent development of new pesticides has been concentrated on 'safe pesticide', as it were, that has the highly selective properties without unfavorable side influences on other ecosystem. According to literature cited up to now, feasibilities of safe pesticide development would be summarized as two categories. One of them is the development of chemical pesticides, which include the molecular structure modification of established pesticides for increased safety and synthesis of new safe chemicals which can attack the vulnerable point of physio-ecological characteristics in insect pests and diseases. The other is the biological pesticides which comprise natural enemies and microorganisms to act selectively on confined insect pests and diseases, In addition, improvement of physico-chemical properties of available pesticide formulations would be one of the desirable means for safe pesticide development in view of efficacy enhancement and minimization of hazardous properties or safe pesticide development, various approaches are feasible and needed to study, however, long period and much financial outlay are necessary to develop a new item. And under the present situation in Korea, there are many difficulties for performing research on all the possible routes. Therefore, combined pesticides by the reasonable combination of already registered resticides evaluated as the fairly safe pesticides and safe formulation based on their physico-chemical properties would be developed primarily. And many efforts would be given gradually for the development of new chemical and biological pesticides.

• Journal of Biosystems Engineering
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• v.5 no.2
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• pp.26-39
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• 1980

A study was investigated to find out the mechanical optimum conditions of power tiller-plow system on both paddy field and upland. Mathematical model was developed for the theoretical analysis of this system and the experimentation on the field was carried out with two different sizes of 5PS and 8PS power tiller equipped with rubber tire. 1) The relationship between the plowing depth and draft resistance of the power tiller-plow system was a quadratic function. 2) The minimum point of the specific draft resistance of the 5 PS plow was found at the smaller plowing depth than that of 8 PS plow, therefore we can find that the curved surface of 5PS plow bottom should be improved for the effective plowing operation. 3) As the improvement of the mechanical balance by the desirable change of the curved surface of plow bottom, the relative position of hitch point and dimension of plow beam would be realized, the 5 PS power tiller could be used to plow deeply (about 16-17cm). 4) The virtual acting point of the total draft resistance on the plow bottom approached to the land side as the plowing depth increased. 5) The resultant of vertical reaction force $R_2$ on the landside was increased with the plowing depth, while the vertical reaction force $R_1$ on the wheel was decreased as the slope angle of the body of power tiller increased. 6) For the effective plowing operations ; a) The slope angle of the body should be as small as possible. b) The diameter of the wheel should be as small possible. c) The horizontal and vertical distances $l_2, h_1$ between the wheel axis and plow bottom should be as large as possible. 7) To use the 5PS power tiller as the major unit of agricultural machinery, the curved surface of the 5 PS plower bottom and the mechanism of attachment between the power tiller and the plow should be changed as the indications of this study, and in addition to these, the new operation method of the field work should be developed.

• Atmosphere
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• v.27 no.4
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• pp.455-466
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• 2017

In Korea, property and human damages occur annually due to heavy precipitation during the summer. On August 8, 2015, heavy rainfall occurred in the Seoul metropolitan area due to an outflow boundary, and $77mmhr^{-1}$ rainfall was recorded in Gwangju, Gyeonggi Province. In this study, the simulation of the WRF numerical model is performed to understand the cause and characteristics of heavy rainfall using the Conditional Instability of the Second Kind (CISK), potential vorticity (PV), frontogenesis function, and convective available potential energy (CAPE) analyses, etc. Convective cells initiated over the Shandong Peninsula and located on the downwind side of an upper level trough. Large amounts of water vapor were supplied to the Shandong Peninsula along the southwestern edge of a high pressure system, and from the remnants of typhoon Soudelor. The mesoscale convective system (MCS) developed through CISK process and moved over to the Yellow Sea. The outflow boundary from the MCS progressed east and pushed cold pool eastward. The warm and humid air over the Korean Peninsula further enhanced convective development. As a result, a new MCS developed rapidly over land. Because of the latent heat release due to convection and precipitation, strong potential vorticity was generated in the lower atmosphere. The rapid development of MCS and the heavy rainfall occurred in an area where the CAPE value was greater than $1300Jkg^{-1}$ and the fronto-genesis function value of 1.5 or greater coincided. The analysis result shows that the MCS driven by an outflow boundary can be identified using CISK process.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.2
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• pp.139-146
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• 2011

The breaking wave pressure occurs when a plunging breaker instantaneously impinges on structural surface, and appears differently depending on whether or not to form air pockets at the instant of contact. The Wagner type normally forms a single pressure peak at the contact spot due to the direct collision of water volume to the structure whereas in the Bagnold type the time lagged oscillation of the air pocket causes pressure peaks even at areas away from the spot. In the present study, the Bagnold's impact pressure is numerically and experimentally investigated for the bulkhead of an underwater tunnel under construction which is subjected to nearby breaking waves. A numerical solver of Navier-Stokes equations was applied to reproduce the breaking waves near a bulkhead, and the results showed the Bagnold's impact pressure occurring on the back (land side) face of the bulkhead. The existence of the impact pressure was also verified by a hydraulic model testing, and it was found that the experimental results well conformed to their numerical counterparts.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.404-410
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• 2009

This study was carried out to develop a self-propelled type explosive subsoiler for improving the root zone soil conditions in orchard and other forest fields. Prototype was designed to be able to inject air and other soil improving material such as lime into soil at the same time, and thus improve the air permeability and drainage of orchard soils to promote the root growth of tree for high quality fruit production. Soil penetration device of explosive subsoiler is composed of air hammer, penetration rob and air injection nozzle. To support the soil penetration device of explosive subsoiler to penetrate vertically, modified Scott-Russel mechanism was used. Timing control device for simultaneous injection of soil improving material with air was attached to the out side wall of air cylinder and as the cylinder move, the soil improving material was injected into soil at the same time. Turning radius of prototype was 2.2-2.3 m with good mobility in sloped land. It took approximately 1 minute for lime injection system to reach the optimum pressure of 9.9 kg/$cm^2$, average 10-20 seconds were required to rupture soil with the depth of 50 cm and 2-3 seconds were required for explosion, so all in all about 1 minute and 20 seconds were required for one cycle of explosion. Maximum soil rupture depth and diameter were 50 cm and 3-4 m respectively depending on the soil type and soil moisture content. For final design of explosive subsoiler inclination angle of lime hopper was increased from 60 degree to 70 degree and the shape of hopper was changed from rectangular cone to circular cone to solve the clogging problem of lime at out let. Agitating system operated by compressed air was attached to the metering device of the prototype, thus more than 90 cc of lime was discharged per cycle from metering device without clogging problems.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.354-362
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• 2015

In this study, for integrated management and inter-exchange of operational data generated by ships and land-side information on safe and business, a vessel communication system with modular functions was designed that applied high efficiency compression, least-cost algorithms and Inmarsat FBB connection automation system. Performance test at the KTsat Kumsan satellite earth station; system was found to delivered an average transfer speed of 7 kB/S, which was significant improvement from the existing commercial product's average speed of 5 kB/S. It also delivered twice the efficiency of the existing product in terms of compression rate and transfer of the most widely used office files in maritime businesses.